Improvement in hoisting device



-JL'L DOYLE.

Hoistng Device.

Patented 1am 8, 186k UNITED STATES PATENT OEEicE@ JOHN JAMES DOYLE, OF NE`W YORK, N. Y.

IMPROVEMENT IN HOISTING DVlC.

Specification forming part of Letters Patent No. 31,077', dated January S, lSGl.

To @ZZ whom if; may concern:

Be it known that I, .I OHN JAMES DOYLE, of the city, county, and State of New York, have invented a new and Improved Hoisting Device; and I do hereby declare that the following is afull, clear, and exact description of the same, reference being had to the annexed drawings, making a part of this specification, in` which-- Figure l is a side view of my invention, the sides of the shells of the blocks nearest the eye being removed, Fig. 2, an edge view of the same, the shells of the blocks being bisected centrally; Fig. 3, a cent-ral section of the upper block of the same.

Similar letters of reference indicate corresponding parts in the several figures.

The object of this invention is to obtain a powerful and at the same time a simple and compact hoisting device capable of general application, but more especially adapted to the lifting or hoisting ot' heavy weights.

'lhe invention consists in the employment or use of two pulleys of different diameters and an endless chain, band, or rope applied to the pulleys, and arranged substantially as hereinafter described, whereby the desired end is obtained.

To enable those skilled in the art to fully understand and construct my invention, I will proceed to describe it.

A represents a block, in which two pulleys, a l), are placed and keyed on a common axis, c'. The pulleys o b are toothed; but they are of different dia-meters, and consequently one has more teeth than the other, the dilt'erence in the number ot' teeth corresponding to the difference in the diameter of the pulleys, the teeth, of course, of both wheels being' of the same size.

The axis o extends through the shell ot the block A at one end, so that a pulley, d, may be placed on it, and B is an endless chain, which passes around the two pulleys o l) in the block A and around a toothed pulley, e, in a block, O, as shown clearly in Figs. l and 2. rIhe axis of the pulley e may have a crank, f, att-ached, as shown in Fig. 2.

To the block A there are attached two guiderollers, g g-one opposite each pulley o 2)- and a roller, 71, is also attached to the lower part of block A. The Jfunction ot' these rollers will be presently shown. The links of the chain B fit on the teeth et the pulleys ai b, so that all slipping is ellectually prevented. The lower block, (i, has the weight or article D to be hoisted attached to it, and the upper block, A, is suspended by a swivel, E, from any suitable or convenient support, F.

The operation is as follows: rlhe pulley d of the upper block, A, or the pulley c. et' the lower block, C, may be rotated by any convenient power, and at every revolution ot the pulleys a l) in a direction from left to right, as indicated by arrow l, the lower block, t', with its weight D, will be elevated in space a distance equivalent to the difference between the diameters of the two pulleys a l). For instance, it the larger pulley, o, has seventeen teeth and the smaller pulley, l), sixteen teeth, the block O will be elevated vertically acorresponding distance, and the slack of the chain (designated by B) will be increased in length a corresponding distance. \\'hatever power, therefore, is applied to the pulley d or e is multiplied seventeen times in being` transmitted to the weight D through the medium of the ehain B and pulleys o 'The power and speed, of course, may be varied by having' the diameters otl the pulleys a l) vary more or less in relation with each other. rlhe rollers g g 7L serve as guides for the slack portion B of the chain, and keep the latter out of the path of the movement of the lower block, t. By reversing the movement of the pulleys the weight D, ot' course, will descend.

I do not confine mysell:` to a chain nor to toothed pulleys, for equivalent devices may be used. Ropes or bands, for instance, with knots, balls, checks, or stops attached, may be used in lieu ol a chain, and in connection with the above pulleys with embed ded spaces 5 or sectional stops may be used in order to secure a firm and sutlicient grip or hold of the chain, rope, or band in all positions during the elevation, suspension, or descent ol load attached thereto.

This invention may be used for liltin g loads through short spaces, and maybe inclosed in a bloclecasing, similar to the usual liftingjack, and the slack 3 of the chain B may be attached to the barrel or roller ol' any windlass or hoisting-gin, for the purpose et increasing the power or convenience in the working' otl the same.

Having thus described my invention, what l.

chain B, or its equivalent, the pulley e, and guide-rollers g g h, arranged in relation with the chain B to operate as and for the purpose set forth.

JOHN JAMES DOYLE. \Vitnesses:

C. W. CoWToN, M. M. LIVINGSTON. 

